Damage of concrete with epoxy coated reinforcement due to corrosion, freeze-thaw and fatigue with application to bridge decks .

摘要

The deterioration of reinforced concrete bridge decks due to corrosion of the steel bars is a common problem. Epoxy coated reinforcement (ECR) is known to perform better than plain (black) steel, but the appropriate maintenance schedule for ECR bridge decks is not well established. The goal of this project was to compare damage of concrete reinforced with ECR and black steel due to corrosion, freeze-thaw, and fatigue loading for application to bridge decks.;Concrete specimens with ECR and black steel reinforcement were artificially aged using freeze-thaw cycling and accelerated corrosion to simulate the varying ages of bridge decks. These specimens were repaired and then simultaneously subjected to fatigue loading, freeze-thaw cycles, and continued accelerated corrosion to simulate the loading on bridge decks.;Two methods were used to compare the deterioration of specimens with black steel and ECR. The first method was based on corrosion data. It was found that the corrosion rate was about 2.5 times lower for ECR than for black steel, implying that the effects of corrosion-induced damage appear more slowly in ECR. The second method utilized X-ray tomography to obtain images of internal cracking in the specimens. Image-processing software was used to compute the volume of cracks inside the specimens. It took about 4 times longer for the ECR specimens to have the same volume of cracks as black steel specimens. The damage was insensitive to the type of repair performed.